At his concert in Boston on Saturday, Bieber played an acoustic guitar and sang Justin Timberlake‘s hit, “Cry Me A River,” a song with lyrics that describe the feeling of finding out a partner has been cheating.

It’s unclear whether or not Bieber’s song choice deliberately referred to Gomez, 20, who ended the relationship more than a week ago, a source told PEOPLE. Bieber has reportedly played the song before.

Bieber, 18, hasn’t addressed the breakup directly. “I don’t know what to say,” he told John Garabedian on his Open House Party radio show on Saturday. “I don’t know really what’s even going on in my life, so … to even assess that doesn’t make sense ’cause I’ve not made any comment.”

Meanwhile, Gomez stepped out for a promotional event at Kmart in White Plains, N.Y., on Sunday, and was photographed holding hands with a female friend.

“Thank you everyone who came out to Kmart today,” she Tweeted. “Such a warm welcome to my first visit to White Plains. Love you all.”